That God is the Savior of all is scandalous to the self-righteous Christian. The very thought of God saving all snares them.
You see, they’ve earned it — so they think — they’ve done all the right things in the right way.
Whether it be the right prayer(s), the right charity work, the right bible reading and preaching, — They’ve even “received” God’s “free” gift in the right kind of way. No one else has, according to them, so they are quite sure, that God is not going to save all who did not “receive” the “free” gift, like they “received” it.
Have you ever tried to talk to a 10-year old, who doesn’t quite get grammar, figures of speech, word usage, tone, etc… and the kid misses the meaning of what you said? And not only do they miss the meaning, but they are so proud of their misunderstanding and brag that they’ve gotten one over on you.
The self-righteous are this way.
God is not really the “savior of all” they insist… yes, he is “potentially” the savior of all… but not really.
They are so sure of their “rightness” that it makes them angry to suggest that God would show favor to those who deserve the opposite.